An Illinois Certificate of Counsel Pursuant to Supreme Court Rule 604(d) (604(d) Certificate) is a legal document issued in the State of Illinois that attests to the fact that the attorney filing the certificate has consulted with the client regarding the potential merits of the case and the risks associated with going ahead with the case. The 604(d) Certificate is also referred to as a Certificate of Diligence or a Certificate of Merit. There are four types of 604(d) Certificates: Certificate of Merit, Certificate of Diligence, Attorney's Certificate, and Affidavit of Counsel. The Certificate of Merit is the most common type and is used when an attorney is representing a client in a civil action. This certificate attests to the fact that the attorney consulted with the client and was able to determine that the client's case has potential merit. The Certificate of Diligence is similar to the Certificate of Merit but is used when the attorney believes that the case has merit, but there is not enough information to determine whether it has potential merit. The Attorney's Certificate is used when an attorney is representing a client in an arbitration or mediation. This certificate attests to the fact that the attorney consulted with the client and was able to determine that the case has potential merit. The Affidavit of Counsel is the least common type and is used when an attorney is representing a client in a criminal action. This affidavit attests to the fact that the attorney consulted with the client and was able to determine that the case has potential merit. The 604(d) Certificate is important because it provides an assurance to the court that the attorney has consulted with the client and has determined that the case has potential merit. This document is required in order for a case to proceed in the state of Illinois.